The present invention relates to a bevel gear mechanism, especially a bevel spur-gear mechanism having one or more gear mechanism stages.
Known bevel gear mechanisms form a compact drive unit in a drive train together with the output side work machine, the drive side motor on the bevel pinion shaft, the couplings and further auxiliary units. In particular, couplings, service brakes or fans individually or in common are frequently installed in the shaft train between the motor and the input shaft of the gear mechanism with the bevel gear stage. For such components, to protect against rotating parts, various housings are known between motor and bevel gear mechanism, and can be configured in the shape of simple covers or housing cages that can be mechanically stressed.
The known bevel gear mechanisms for such a drive train are, pursuant to the mechanical assembly technique, available in different sizes having the same geometrical features. Such a drive train is frequently mounted on a machine mount base, the gear mechanism beam. With special mounting variations, the drive motor is supported on the gear mechanism housing by means of the motor cage. The shaft of the work machine carries the weight of the drive unit. A torque support prevents the rotation of the drive train. Such gear mechanisms exist for all conceivable installation positions, and with different structural forms of the drive and output shafts. Characteristic is the use of a largely unaltered main housing not only for the spur-gear mechanism but also for the bevel spur-gear mechanism.
DE 1 000 654 A discloses the mounting of a bevel pinion shaft of a bevel gear mechanism in a bearing bushing that is introduced into a long, one-piece housing bore, and that has a flange at one end. The bearing bushing surrounds the pinion shaft, the interior of which is guided by roller bearings, and together with further components forms an assembly that can be easily pre-mounted. The housing bore extends axially over the length of the cylindrical outer peripheral surface of the bearing bushing. The long, deep bore easily aligns the assembly and has the required rigidity. The required contact pattern in the tooth engagement of the bevel gear stage can be established by shims between the flange of the bearing bushing and the gear mechanism housing, or via axially acting adjustment mechanisms. The drawback of such a construction is the very great axial installation space requirement not only for the bearing bushing but also for further components in the drive train between motor and gear mechanism.
DE 1 984 404 U describes the arrangement of a fan wheel on the hub of a coupling flange that is mounted on the drive shaft of the bevel gear mechanism. The conical housing neck, which is part of the gear mechanism housing, and that surrounds the bearing bushing having the bevel pinion shaft, is not altered by the additional arrangement of the fan wheel. The fan is adapted to the prescribed contour of the gear mechanism in such a way that the blades also surround parts of the housing. The fan hood that is adapted to the fan must guide the air stream along the conical housing neck of the bevel gear stage to the gear mechanism housing. The drawback of such a design is the axially wide stretches that the air stream must overcome to reach the surfaces of the gear mechanism housing. Another drawback is the complicated configuration of fan and fan hood. In addition, the fan hood is not suitable to realize the necessary protection against access in the region of the coupling.
US 2006/0000301 A1 discloses a gear mechanism housing for a bevel spur-gear mechanism that has a spacer flange formed on the gear mechanism housing and that is produced as a one-piece cast part. The spacer flange contains a plurality of openings through which an air stream produced by a fan wheel passes and is guided in channels to the gear mechanism housing. The integrally molded bearing flange is mounted at an end ahead of the housing neck of the bevel pinion shaft, and leads to a disadvantageously long axial space requirement for the drive unit. The end flange of the bearing bushing of the bevel pinion shaft is similarly supported in the bearing flange and, due to its radial dimensions, displaces the air passage openings in the integrally molded spacer flange very far to the outside, so that here due to the large radial minimal diameter drawbacks with regard to flow dynamics result for the beginning of the openings.
The known combination of individual components of the gear mechanism from a prefabricated parts assembly program to form a drive train always leads to a long overall drive construction. Furthermore, the defined interface locations between the individual components in particular hinder the function of the fan. The fans can be differentiated by two different operating principles. Axial fans convey an air stream in the axial direction over the entire fan cross-section. A drawback is the conveying direction of the air, which is a function of the direction of rotation. Radial fans draw the air in the region of the drive shaft and convey it radially outwardly along the blades of the fan. Here cooling baffles or hoods must deflect the air stream in a defined manner. The radial fans can particularly advantageously be designed so as to be independent of the direction of rotation. The drawback is the intake of air in the region of the shaft. The interface parts or locations of the adjoining structural elements in the drive train routinely obstruct the conveying effect of the radial fan via their inlet housings, such as, for example, the cover hood of a coupling. The optimization of individual components, such as, for example, of fans and fan hoods, in cooperation with a bevel gear mechanism, alone does not lead to any significant improvements.
The object of the present invention is to improve the bevel gear mechanism of the aforementioned general type that is constructed pursuant to the mechanical assembly technique in such a way that a drive unit that is composed of bevel gear mechanism and electric motor, and that has a compact, axially short construction and at the same time a high rigidity, can also be achieved for a large motor output. In addition, an application-dependent equipping with auxiliary units, such as couplings and brakes, should not lead to an obstruction of the air supply for the cooling of the drive unit.